What are the downsides of Cat6a cables?
Cat6a's main drawback is that it may outpace your actual needs. It carries 10 Gb/s over 100 metres, yet many devices still run at or below 1 Gb/s, so cheaper Cat5e or Cat6 cable can often do the same job. Whether Cat6a costs more or is harder to install depends on the specific product, so verify both against the actual listing.
Cat6a is the category that takes copper Ethernet to 10 Gb/s across a full 100-metre channel, a standard ratified in 2009. That capability is its selling point, but it is also where the drawbacks start. Fluke Networks notes that Cat6a was arguably ahead of its time: only in roughly the past five years have common LAN applications required 10 Gb/s to the end device, and many devices still operate at or below 1000 Mb/s. In other words, a lot of Cat6a capacity sits unused in typical setups.
[1]Downside one: paying for speed you may not use
The clearest drawback is overprovisioning. Fluke Networks notes that with qualification testing, some installed Cat5e and Cat6 cabling can support 2.5 and 5 Gb/s to 100 metres for Wi-Fi 6 deployments, and potentially 10 Gb/s to 55 metres or less. Cat6 on its own supports 10 Gb/s only up to about 35 metres. So if your runs are short and your devices top out at gigabit speeds, a lower category may cover the job. The catch is that no pricing comparison between categories is established here, so treat "Cat6a costs more" as an expectation to verify against dated retailer offers for the specific product rather than a fixed rule.
[1][2]Downside two: claims about thickness and handling vary by product
You will often read that Cat6a is thicker, stiffer and harder to pull through conduits than Cat6. That may well be true for many products, but construction varies between shielded and unshielded variants and between manufacturers, so treat it as a product-specific question rather than a category-wide rule. What the standards do establish is the performance envelope: Cat6a is rated to 500 MHz versus 250 MHz for Cat6. A higher frequency rating is not the same thing as a larger outside diameter. Before assuming a handling penalty, check the actual product's specifications rather than relying on the category name alone.
[1]Downside three: compatibility is about the whole link, not the cable
A Cat6a cable does not make a network faster by itself. Speed is negotiated across the whole link: the cable, the connectors on both ends, and the ports on your switch and device. Plugging Cat6a patch leads into gigabit equipment still runs at gigabit. Conversely, mixing a Cat6a lead into a run of lower-category fixed cabling does not upgrade that run. The Networks & Cables buying checklist makes the same point from the buyer's side: match both connector ends, check cable length and category, and confirm speed, shielding and PoE requirements before comparing prices.
[1][2]A concrete comparison
As a hypothetical example, imagine a small office with a 20-metre run from the switch to a desk computer whose network card is gigabit. Cat6a would deliver 10 Gb/s capability that nothing on either end can use. Cat6 alone supports 10 Gb/s up to about 35 metres, so even a future upgrade to 10 Gb/s equipment could potentially work on that short run with the cheaper cable, though this depends on qualification testing rather than the category label alone. Now imagine the same office planning a 90-metre run to a 10-gigabit server link. There, Cat6a is the category designed for the job, and the extra capability stops being a downside.
[1]What to do next
- List the devices on each run and their actual port speeds, since many still operate at or below 1000 Mb/s.
- Measure your longest cable run: short runs may be within reach of lower categories, while runs near 100 metres at 10 Gb/s point to Cat6a.
- Match both connector ends and confirm shielding and PoE needs before comparing prices, because similar model names can hide different specifications.
- Compare dated UK offers for the exact product code, and confirm today's price and availability with the retailer, since recorded prices can change.
The practical next step: work out the speed your slowest device actually needs and the length of your longest run, then compare like-for-like offers for the lowest category that covers both. If that exercise points to Cat6a, buy it with confidence; if it points to Cat5e or Cat6, you have just avoided paying for headroom you would never use.
[1][2]Sources and dates
- https://www.flukenetworks.com/blog/cabling-chronicles/ethernet-cable-history · accessed 2026-10-18
- https://networksandcables.com/ · accessed 2026-10-18